def say_hello()->None:
    """
    打招呼函数
    """
    print("hello,world")
    print("hello,world")
    print("hello,world")
    
def sum(a,b):
    """两个数相加

    Args:
        a (_type_): _description_
        b (_type_): _description_

    Returns:
        _int_: 两个数之和
    """
    return a+b

def max(a,b):
    """求最大值

    Args:
        a (_type_): _description_
        b (_type_): _description_

    Returns:
        _type_: _description_
    """
    if a>b:
        return a
    return b 


def ca(a,b):
    """
    使用元组返回多个值
    """
    #两个数乘机
    mul = a*b
    if b == 0:
        return mul,None
    #两个数的商
    div = a/b
    
    return mul,div #自动组包元组



print(ca(3,0))
"""say_hello()
print(say_hello()) #返回值为none
print(sum(3,4))
print(max(1,8))"""

